<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <link rel="stylesheet/less" type="text/css" href="./media_test.less" />
    <script src="./less.js"></script>
    <title>Document</title>
</head>

<body>
    <div class="sky">
        重置浏览器查看大小。当浏览器窗口的宽度小于 300 像素时，背景颜色会变成淡蓝，否则是淡绿色
    </div>
</body>

</html>